• TI Thinks Resolved

TPA3128D2EVM: Idle output waveform

Intellectual 2300 points

Replies: 5

Views: 68

Part Number: TPA3128D2EVM

Hello,

When probing one of the audio outputs of the TPA3128 with respect to ground (i.e. single ended) while idling, my customer sees a waveform like that shown below. It doesn't look like normal output ripple and we are curious as to what is causing it. Is this expected?

Thanks,

Michael

  • Hi Michael,

    Were there any modifications done to the TPA3128D2EVM or was everything in default configuration?

    Best Regards,

    Robert Clifton

  • In reply to Robert Clifton56:

    Hi Robert,

    We didn't make any modifications to the TPA3128D2EVM. We did have the PVCC and AVCC rails shorted together and used a 24V power supply, 600kHz switching frequency. Tried both single ended and differential audio in configuration with low Idle Loss Mode selected. Loaded it with 8ohms, since the output was oscillating when unloaded.

    Thanks,

    Michael

  • In reply to Michael Balourdas:

    Hi Michael,

    That's switching noise, but it is supposed not too high.

    Did you modify PVCC power decoupling caps?

    Regards,

    Derek

  • In reply to Yanming Gong:

    Hi Derek,

    No modifications were made to the EVM.

    Thanks,

    Michael

  • In reply to Michael Balourdas:

    Hi Michael,

    I suggest you can add some decoupling caps on PVCC power to filter the noise.

    Regards,

    Derek